How to Make a Photo Cell

Resistor image by Andrzej Thiel from

Things You'll Need

  • Propane torch
  • Sheet of copper
  • Salt solution
  • Copper wire
  • Small block of wood

Photocells are used in watches, traffic lights, alarms and much more. Photocells have many different purposes and continue to be used in light, sensitive machines to determine whether or not current should flow to the machine or not. Although the photocell is used in many large-scale projects, you can also make your own photocell quite quickly and easily.

Heat up a relatively small area of a sheet of thin copper with a propane flame. Continue heating the copper sheet until it is glowing with heat. Let the copper cool for a moment.

Place a drop of salt solution on the copper plate. Make contact with the solution with clean copper wire.


Attach the copper wire to a small block of wood. This will keep the copper wire in place by simply positioning the block of wood near the copper plate. The plate will serve as one terminal, and the copper wire will be the other, which together form the cell. Connect the cell across a volt meter to test the voltage.


About the Author

Writing in both Spanish and English, Martin Adamovic has been covering psychology, marketing, lifestyle and sports since 2009. She has served as a sports journalist for a variety of mobile sports applications in Europe, including General Mobile and Bravo Game Studios. Adamovic holds a B.A. in Spanish and business from the University of Colorado and is currently studying law.

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